From the Wikipedia entry on "Lutheranism:"

While not an issue in the majority of Lutheran church bodies, some of them forbid membership in Freemasonry. Partly, this is because the lodge is viewed as spreading Unitarianism, as the Brief Statement of the Missouri Synod reads, "Hence we warn against Unitarianism, which in our country has to a great extent impenetrated the sects and is being spread particularly also through the influence of the lodges."[58] A 1958 report from the publishing house of the Wisconsin Evangelical Lutheran Synod states that, "Masonry is guilty of idolatry. Its worship and prayers are idol worship. The Masons may not with their hands have made an idol out of gold, silver, wood or stone, but they created one with their own mind and reason out of purely human thoughts and ideas. The latter is an idol no less than the former."[59]

Lutheranism, available http://en.wikipedia.org/wiki/Lutheran

Good to hear that it isn't an issue in a majority of Lutheran church bodies. I know my ELCA Lutheran congregation is full of Brother Masons and the Pastor's neighbor is a Mason. When I had some questions about some of the "rough edges" I found in our ritual, even the Pastor told me that I was focusing too much on words and not enough on message.

At any rate, let us address the first charge, namely that of the lodges spreading Unitarianism. For those who wouldn't otherwise understand, Unitarianism is the belief that God has only one manifestation and that Jesus and the Holy Spirit are not God. This belief is in direct opposition to Trinitarian theology (Three-in-one as most Christian churches preach today). Now, the number one counter argument to this is that MASONRY DOESN'T TEACH THEOLOGY. Must I reiterate? NO THEOLOGY. Even if one were to take Masonic ritual as some sort of theological statement, where would there be any teaching of Unitarianism? Would simple omission of specific references to Jesus and the Holy Spirit constitute Unitarianism? If so, then having your church's "daily bible reading" come solely from the Old Testament would also constitute teaching Unitarianism. Sorry, but I cannot abide the idea that failure to teach a specific belief means teaching the opposing belief. If that were the case, then Masonry wouldn't be the only (or even the biggest) "offender."

The second charge, that of idolatry, is an interesting and original one. The idol they accuse us of worshiping is that of human intellect. This one is more difficult to counter since I cannot prove or try the hearts of my Brother Masons. But I can prove and try the lessons taught in the three Masonic degrees.

Entered Apprentice: You are first informed that you must profess a belief in a being that is greater than yourself. By definition, your ideas and thoughts are not greater than yourself so this is not, in itself, teaching idolatry. You are next taught that no man should ever engage in any great or important undertaking without first invoking the blessing of Deity. An extension of this would be to say that it would be folly and futile to proceed in something that is not begun with the blessing of God. This lesson cannot constitute teaching idolatry since it discourages the creation of anything not blessed by God. As the degree progresses, a candidate invokes the name of God (however He is known to the individual candidate), that He should bear witness to the solemn and important work that is now being undertaken. This cannot be idolatry because God is called upon to witness to our intentions in the business in which we are then engaged. We are not holding up our intentions as the rule by which our work is to be tried. Instead, we are asking God to be our witness to our intentions, that He try our work so that it doesn't become idolatrous. Here is the closest Masonry ever comes to teaching theology and it's far from teaching idolatry. After that, a candidate is invested with a lambskin, or white leathern apron, and told that it is his to wear throughout a virtuous life. He is reminded that his behavior ought to be such that he is beyond reproach before his fellow man. Is this the idolatry they're talking about? Teaching that a man's word ought to be reflective of the virtues he has been taught? If so, then the Bible teaches the same idolatry. The lecture that accompanies the Entered Apprentice Degree teaches that a man's priorities in this life ought to be Faith in God, Hope in immortality, and Charity to all mankind. He is also taught that his endeavors are doomed to failure unless they have the blessing of God. Finally, he is taught that the Holy Bible is to be the rule and guide of his faith and should he ever be at a loss for instruction, that this excellent and inestimable gift of God to Man will provide him with all the direction he needs. This can hardly be considered idolatry since God himself told us that the Holy Bible is useful for instruction and reproof of our actions.

Fellowcraft: In the first section, the candidate learns that his responsibilities extend far beyond himself and are thus enumerated: To God, in always holding Him to be the chief Good in the world and never mentioning His name except with that reverential awe due from a creature to his Creator; to his country, in being a quiet and peaceable citizen of his community; to his neighbor, in always being ready to assist in any manner possible; and to his family, in being their provider and strength in times of need. Can these be teaching a man to worship human thoughts and ideas? Are these ideas from man or from God? These lessons are the same as those taught in the Old and New Testaments. They are not the damnable lies of Satan or the empty gestures of man, but the true fruits of the Kingdom of God as taught by Jesus in his sermons and parables. In the second section, the candidate's attention is directed toward the instruments by which we measure and study God's creation. He is encouraged to undertake the study of the seven liberal arts and sciences as a way to further his understanding of God's divine plan and be better enabled to usefully apply himself to the practice and exercise of every good work and virtue. Could this be teaching a man to worship that which is created rather than He who created? It would be a very misguided man who interprets the lessons in that way.

Master Mason: The candidate is shown an example of true courage and fortitude in the face of baser motives. It affords the candidate a time to reflect on his own conscience and search his heart for all the virtues he has learned, trying his own desires against them. The lessons taught in the Master Mason lecture are those things that empower a man to lead a life where he can be most useful to his fellow creatures. He is taught to square his actions against the virtues found in the Holy Bible. He learns to meet all men on the level of equality and that his conduct should always be upright in his several stations before God and man. He is taught to break off the rough edges of his conscience and measure and lay out his days so as to maximize his usefulness. He is taught to spread the cement of true friendship and compassion to unite mankind into one common mass of good will toward others. Finally, he is afforded a striking look at the temporary nature of human life and shown that while many calamities may befall a man and sever his thread of life, yet there exists that spark of life that, given by Almighty God when he breathed life into Adam, can never die. Did man create this spark of life? Can he one more minute add by his own endeavors? This is not the lesson. The lesson is clearly one of reliance on God for all things.

Masonry, in its several parts, is NOT guilty of teaching the idolatrous worship of the works of human hands, nor is it guilty of teaching the likewise idolatrous worship of ideas.

Further amplification on the nature of Masonic teaching:

Masonry does not teach theology. The word "theology" comes from the Greek "theos," "a god," and "logos," "study." If, therefore, "theology" is the study of God, a god, or gods, then Masonry is incapable of teaching it. Masonry encourages a man to study and follow his religion. In this way, Masonry encourages the study of God, but such things cannot be taught except by one's religious faith.

There is nowhere in Masonry where a candidate is taught anything about God. God is not given a name in any Masonic ritual. No characteristic is attributed to Him. Each individual man must find out those truths for himself. As is taught in Masonry, a man's duty begins with God. In this way, should a man ever find conflict with the teachings of Masonry and the tenets of his religion, those truths he knows in his heart and which come from his professed faith must come first. In short, there is no way a man can become weaker in faith toward God by hearing the lessons taught by Masonry any more than he can lose his faith by reading a book of poetry or hearing a concerto.